A seat in a vehicle includes a seat back and a seat bottom. When the vehicle experiences a crash, crash forces tend to move an occupant of the seat relative to the seat. For example, the vehicle may experience a crash in which an impact is directed against the rear end of the vehicle. Crash forces then act against the vehicle in a forward direction. Such crash forces may cause the occupant to move relative to the seat in a rearward direction, and thereby to move forcefully against the seat back.